Re: ballasting

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <herwig.roscher-at-gmx.de>


Peter Komen wrote:
> but maybe I can theorize a little.

Peter,

Thank you for your response.

> I don't know the wall socket voltage or AC frequency in Germany.  May
> not be applicable to this discussion.
- It's 230 V / 50 Hz, but theory should work on all voltages and 
frequencies.
 
> Wired wall socket to MOT to halogen light to wattmeter back to wall
> socket? 
- Exactly!

> I would expect  some non-linear function to calculate the inductance
> relative to the halogen light resistance.  This would be complicated by
> the changing resistance of the halogen light. 
- Agree. I chose the halogen light, because it was on hand and 
because e.g. heating elements show the same nonlinear behavior.

> If this was run without the light, you should be able to calculate the
> magnetizing inductance. 
- Some time ago I calculated the magnetizing inductance of this MOT 
to be 200 mH and the leaking inductance to be 53 mH.
 
> Much lower inductance; lower than welder with open secondary. 
- The inductances of MOT and welder are NOT in the same order of 
magnitude. I wanted to find out, whether there is a difference 
between a current-limited ballast like an arc welder and a less-
current-limited ballast like a MOT concerning an open versus a 
shorted secondary winding.

> Can you hook to wattmeter in series with just the MOT or Welder and
> run these tests?
- Unfortunately the wattmeter is limited to 2200 W and connecting a 
tranny with shorted secondary winding most certainly would fry it.

> Be careful because I could be wrong.
- Me too.

BTW: Instead of inductive ballasts one could use capacitive ones.
Besides of changing the phase relationship, which could make the
correct alignment of a RSG difficult, are there any other drawbacks?
Why are inductive ballasts used mostly?

Cheers,

Herwig
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Greed is the root of all evil!
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